Spring 1544: Now that she is with child, Bianca is more determined than ever to distance herself from her father, disgraced alchemist Albern Goddard. But in this fourth outing (after Death at St. Vedast), when the deadly new element Albern has discovered is stolen and a woman is found murdered by mysterious means, he is panicked and expects his daughter to help. As her husband John is conscripted into King Henry's army, Bianca must navigate a treacherous path among apothecaries, chandlers, and scoundrels, to find out who among them is willing to kill to possess the element known as lapis mortem, the stone of death.